Phase transitions and soft elasticity of smectic elastomers

TL;DR

This paper investigates phase transitions in smectic elastomers, revealing that smectic-C and biaxial phases exhibit soft elasticity similar to nematic elastomers, through three theoretical models.

Contribution

It introduces three models to analyze phase transitions and emergent soft elasticity in smectic elastomers, highlighting their symmetry-breaking and elastic properties.

Findings

Smectic-C and biaxial phases show soft elasticity.

Transitions involve symmetry breaking from $D_{ ext{infty}h}$ to $C_{2h}$ or $D_{2h}$.

Elastic behavior analogous to nematic elastomers.

Abstract

Smectic-C elastomers can be prepared by crosslinking, e.g., liquid crystal polymers, in the smectic-A phase followed by a cooling through the smectic-A to smectic-C phase transition. This transition from $D_{\infty h}$ to $C_{2h}$ symmetry spontaneously breaks rotational symmetry in the smectic plane as does the transition from a smectic-A to a biaxial smectic phase with $D_{2h}$ symmetry. We study these transitions and the emergent elasticity of the smectic-C and biaxial phases in three related models and show that these phases exhibit soft elasticity analogous to that of nematic elastomers.